Autism spectrum disorder (ASD) is a pervasive developmental disorder that causes severe and pervasive impairment in thinking, feeling, language, and the ability to relate to others. Individuals affected with ASD do not necessary exhibit signs of mental retardation. The onset is generally before the age of 3 years, and is usually first diagnosed in early childhood. ASD can range from a severe form, called autistic disorder, through pervasive development disorder not otherwise specified (PDD-NOS), to a much milder form, Asperger syndrome. ASD also includes two rare disorders, Rett syndrome and childhood disintegrative disorder. ASD has a prevalence of 0.6% in the population, affecting many more boys than girls.
Currently there is no single best treatment for all children with ASD nor is there a simple diagnosis method for the disorder. One point that expert professionals agree on is that early intervention is important; another is that most individuals with ASD respond well to highly structured, specialized programs. As soon as a child's disability has been identified, it is recommended that the intervention programs should be started. Effective programs teach early communication and social interaction skills. In children younger than 3 years, appropriate interventions usually take place at home or at a child care center. These early intervention programs typically target specific deficits in learning, language, imitation, attention, motivation, compliance, and initiative of interaction. Included are behavioral methods, communication, occupational and physical therapy along with social play interventions.
Although early intervention has been shown to have a dramatic impact on reducing symptoms and increasing a child's ability to grow and learn new skills, it is estimated that only 50 percent of children are diagnosed before kindergarten. Currently there is no method of early diagnosis and/or predictive method for autism. Parents are usually the first to notice unusual behaviors in their child. In some cases, the baby seemed “different” from birth, unresponsive to people or focusing intently on one item for long periods of time. The first signs of an autism spectrum disorder can also appear in children who had been developing normally. When an affectionate, babbling toddler suddenly becomes silent, withdrawn, self-abusive, or indifferent to social overtures, something is wrong.
Twin and family studies have estimated the heritability of autism as being up to 90%, making it one of the most heritable complex disorders. Rare genetic syndromes and known chromosomal anomalies explain roughly 10% of cases of autism, including Fragile X, tuberous sclerosis, Smith-Lemli-Opitz syndrome, and maternally-inherited duplications of the Prader-Willi/Angelman syndrome region (15q11-13). However, despite high heritability, genetic studies to date have not provided substantial insight into the 90% of autism with idiopathic etiology.
Therefore, there is a need for an early diagnosis method and also methods of predicting whether a fetus, an infant or an individual is at risk of developing autism.